EVILS FOLLOWING DESTRUCTION OF FORESTS. 85 



on the plain, often undermining the confining banks on the 

 right hand and on the left, bringing down the overhanging 

 masses, and sweeping along the dShris and covering fertile 

 lands many feet deep — it maybe fathoms deep — with stones, 

 and clay,, and rubbish, which no appliances of man can 

 remove, and which doom the land to sterility in all coming 

 time — the disturbances of the angle of stability affecting 

 the ground at a level far above that of the torrent, 

 and sometimes occasioning landslips of the most serious 

 importance. 



There may not at first sight appear any connection 

 between the destruction of forests and the occurrence of 

 such phenomena, and yet, as a sand-drift has been known 

 to originate in the uprooting of a bush, miniature torrents 

 have been known to originate in the displacement of a 

 stone half-buried on a mountain side. And by Surrell it 

 has been demonstrated that all the torrents on the Alps 

 — and the Alps are in many places scarred with these — are 

 attributable to the destruction of forests on the mountains. 

 The demonstration is of a most conclusive character — 

 showing that such has been the case in times past ; that 

 such is the case still ; that former torrents have become 

 extinct through the spread of arborescent vegetation over 

 the basin of reception ; and that the artificial planting of 

 trees, or bushes, or herbage, on appropriate sites, has 

 extinguished torrents which immediately before were in 

 full play. 



Many of the phenomena accompanying the creation of 

 these torrents are most remarkable, including stones torn 

 from their beds, propelled above and beyond the rushing 

 water, and advancing through the air in front of the wall- 

 like front of the mountain wave.* But what is of more 

 economic importance is the value of the property, lands, 

 orchards, and houses undermined and carried away ; and 



* Reioisement in Franoe, Ae, (p. 117). 



